Press Contact

UNH Information

Editors/News Directors:
You can reach Mark McConnell, research associate professor in UNH's
Institute for the Study of Earth, Oceans, and Space at 603-862-2047 or by
email at mark.mcconnell@unh.edu. Launches are subject to last-minute
changes. Check the NASA Web site at http://spacescience.nasa.gov.

DURHAM, N.H. -- University of New Hampshire scientists are among those who
will study data from the National Aeronautics and Space Administration's HESSI
satellite, to be launched Feb. 5 from Cape Canaveral Air Force Station in Florida.

Originally schedule for launch in July
of 2000, the HESSI project has been
plagued by numerous delays, most of
which were related to difficulties in
preparing the Pegasus launch vehicle.

The High Energy Solar Spectroscopic
Imager will study gigantic explosions
in the atmosphere of the Sun with a
unique kind of vision, producing the
first high-fidelity X-ray movies of
solar flares and their high energy
emissions.

Within the gigantic flare explosions,
magnetic fields twist, snap and
recombine, blasting particles to almost the speed of light, firing solar gas to tens of
millions of degrees. This action causes the solar atmosphere to sizzle with
high-energy X-rays and gamma rays and accelerate proton and electron particles into
the solar system. Radiation and particles from solar flares sometimes affect orbiting
spacecraft, interfering with communications and astronaut activities.

To understand what triggers a solar flare and how it explosively releases energy,
scientists must identify the different kinds of particles being accelerated, locate the
regions where the acceleration occurs and determine when the particles get
accelerated. The most direct tracer of these accelerated particles is the X-ray and
gamma ray radiation that they produce as they travel through the solar atmosphere.

The UNH project involves using data from HESSI to measure the polarization of
solar flare X-rays. The university's Institute for the Study of Earth, Oceans, and
Space (EOS) was awarded a three-year, $225,000 NASA grant to conduct this work.

"These measurements should provide important insights into the geometry of the
particle acceleration process in flares," says Research Associate Professor Mark
McConnell, principal investigator, who is working on the project with Professor Jim
Ryan. "In other words, are the particles explosively accelerated in all directions at
once or are they somehow accelerated largely in one direction -- or beamed -- guided
by the intense magnetic fields at the flare site? Furthermore, if they are beamed, how
tightly are they beamed?"

Polarization measurements are difficult to make, and past efforts have met with only
limited success. The results from earlier efforts (more than 20 years ago) have been
rather controversial, says McConnell, with no clear results. HESSI provides a unique
opportunity to make the high-quality polarization measurements that are needed.

"The HESSI mission is designed to provide the clearest picture yet of what takes
place during a solar flare," he says. "The polarization measurements are part of the
larger effort to describe what is going on. Only when we have a clear and detailed
picture of what happens during a solar flare will we be able to develop accurate
models that explain how and why it takes place. It is part of the often slow scientific
process that leads to a better understanding of the solar flare phenomenon."

Since HESSI is designed to look at solar flares, getting up during the current solar
maximum period is important to the success of the mission. The solar maximum
represents the peak of the Sun's 11-year cycle. During the peak period, which lasts
for as long as one or two years, the Sun's magnetic fields are more turbulent and
solar flares erupt more often.